Optical substrate and display device

Abstract

The present disclosure provides an optical substrate and a display device. The optical substrate includes: a light guide plate which includes a light entering surface and a light extraction surface adjacent to the light entering surface, and is configured to enable light entering the light guide plate through the light entering surface to be totally reflected toward an opposite surface of the light guide plate opposite to the light entering surface; and a plurality of light extraction structures which is arranged on the light extraction surface of the light guide plate for extracting the totally-reflected light in the light guide plate, and has areas of orthogonal projections of the plurality of light extraction structures on the light extraction surface of the light guide plate gradually increasing along a direction from the light entering surface to the opposite surface.

What is claimed is: 
     
       1. An optical substrate, comprising:
 a light guide plate which comprises a light entering surface and a light extraction surface adjacent to the light entering surface, and is configured to enable light entering the light guide plate through the light entering surface to be totally reflected toward an opposite surface of the light guide plate opposite to the light entering surface; 
 a plurality of light extraction structures which is arranged on the light extraction surface of the light guide plate for extracting the totally-reflected light in the light guide plate, and has areas gradually increasing along a direction from the light entering surface to the opposite surface; 
 a first planarizaton layer covering the light extraction structure and the light extraction surface of the light guide plate and having a refractive index less than a refractive index of the light guide plate; 
 a plurality of beam condensing systems arranged on the first planarization layer and arranged at positions corresponding to the plurality of light extraction structures respectively, wherein each of the plurality of beam condensing systems is configured to adjust a first light beam extracted by a corresponding light extraction structure to form a second light beam, an area of a region irradiated by the second light beam on a plane parallel to the light extraction surface is less than an area of a region irradiated by the corresponding first light beam on a plane parallel to the light extraction surface; and 
 a second planarization layer covering the plurality of beam condensing systems and having a refractive index less than a refractive index of the light guide plate. 
 
     
     
       2. The optical substrate of  claim 1 , wherein the regions irradiated by the second light beam formed by the plurality of beam condensing systems on the plane parallel to the light extraction surface have identical area. 
     
     
       3. The optical substrate of  claim 1 , wherein an orthogonal projection of each of the plurality of beam condensing systems on the light extraction surface completely covers an orthogonal projection of the corresponding light extraction structure on the light extraction surface. 
     
     
       4. The optical substrate of  claim 1 , wherein each of the plurality of beam condensing systems and the light extraction structure has a center of symmetry, and an orthogonal projection of the center of symmetry of each of the plurality of beam condensing systems on the light extraction surface overlaps an orthogonal projection of the center of symmetry of the corresponding light extraction structure on the light extraction surface. 
     
     
       5. The optical substrate of  claim 1 , wherein each of the plurality of beam condensing systems is a lens structure. 
     
     
       6. The optical substrate of  claim 5 , wherein each of the plurality of beam condensing systems comprises a first lens and a second lens, the first lens is arranged at a side of the second lens proximate to the light guide plate, a focal point of the first lens coincides with a focal point of the second lens, the first lens is configured to converge the first light beam to form a converged light beam, and the second lens is configured to adjust the converged light beam to form a second light beam exiting in parallel. 
     
     
       7. The optical substrate of  claim 6 , wherein the first lens is a convex lens, and the second lens is a convex lens or a concave lens. 
     
     
       8. The optical substrate of  claim 6 , wherein parameters of the first lenses in the plurality of beam condensing systems are configured to be not exactly identical, and parameters of the second lenses in the plurality of beam condensing systems are configured to be not exactly identical, so that the regions irradiated by the second light beams formed by the plurality of beam condensing systems on the plane parallel to the light extraction surface have identical area. 
     
     
       9. The optical substrate of  claim 6 , wherein the optical substrate further comprises a beam condensing system substrate arranged between the first lens and the second lens and configured to carry the first lens and the second lens. 
     
     
       10. The optical substrate of  claim 1 , wherein each light extraction structure is a light extraction grating configured to extract and diffract light transmitted in the light guide plate in a collimated manner, and grating characteristic parameters of the light extraction grating are identical. 
     
     
       11. The optical substrate of  claim 1 , wherein the plurality of light extraction structures is a plurality of light extraction gratings; and
 among the plurality of light extraction gratings, the light extraction grating having an area greater than a preset threshold is configured to converge light extracted by diffraction to form a third light beam. 
 
     
     
       12. The optical substrate of  claim 11 , wherein the light extraction grating having an area greater than the preset threshold comprises at least two sub-gratings, and grating characteristic parameters of the at least two sub-gratings are configured to be not exactly identical, so that light extracted and diffracted by the at least two sub-gratings are converged to form a third light beam. 
     
     
       13. The optical substrate of  claim 11 , wherein the regions irradiated by the third light beams converged by the plurality of light extraction gratings on the plane parallel to the light extraction surface have an identical area. 
     
     
       14. A display device, comprising the optical substrate of  claim 1 . 
     
     
       15. The display device of  claim 14 , wherein the display device further comprises a light source arranged at a side where a light entering surface of the light guide plate is located. 
     
     
       16. The display device of  claim 14 , wherein the display device further comprises a counter substrate,
 wherein the counter substrate comprises a black matrix configured to define a plurality of sub-pixel regions, each of the plurality of sub-pixel regions comprises a light shielding region and opening regions arranged at both sides of the light shielding region, a light shielding pattern is arranged in the light shielding region, and the light shielding patterns are arranged at positions corresponding to the light extraction structures respectively. 
 
     
     
       17. The display device of  claim 16 , wherein an orthogonal projection of each light shielding pattern on the light extraction surface at least partially overlaps an orthogonal projection of the corresponding light extraction structure on the light extraction surface. 
     
     
       18. The display device of  claim 14 , wherein the display device further comprises: a light source, a counter substrate, and a liquid crystal layer arranged between the counter substrate and the optical substrate;
 wherein the counter substrate comprises a base substrate and a black matrix arranged on the base substrate and configured to define a plurality of sub-pixel regions, each of the plurality of sub-pixel regions comprises a light shielding region and opening regions arranged at both sides of the light shielding region, and a light shielding pattern is arranged in the light shielding region; 
 wherein the optical substrate further comprises: 
 a first electrode arranged on the second planarization layer; 
 an insulating layer arranged on the first electrode; and 
 a second electrode arranged on the insulating layer and configured to form an electric field together with the first electrode for driving the liquid crystal to deflect.